[Nek5000-users] Nek5000 pertubation mode

[Paul Fischer]

Dear Antonios,

If you can try the current version of the svn repo,
the perturbation code should now work with dealiasing
turned on.

Moreover, you can automatically turn off the base-flow
evolution by setting the number of perturbation modes
(p31 in the .rea file) to be < 0.  Thus, p31=-1 would
give one perturbation mode, no base flow evolution.
The base flow would be defined, e.g., in the useric.

I include an example case in the attached tarfile,
Orr-Sommerfeld evolution.

Paul


On Wed, 3 Jun 2009, Antonios Monokrousos wrote:

> Dear Paul,
> I finally found what the problem with my case was. It was the
> de-aliasing. The problem appears first in the subroutine advabp (file
> perturb.f) where subroutine convop is called (file navier1.f). It seems
> that de-aliasing is not working for the pertubation/linear mode (?) When
> I deactivate the de-aliasing (from the rea file) the result looks correct.
> I tested it also with channel flow and it was the same problem: In
> pertubation mode, with de-aliasing a forcing appears in a few specific
> elements. I haven't been able to understand exactly why this happens but
> I suspect it has to do with the size of the arrays.
> Best regards
> Antonios
>
>
> -- 
> ---------------------------------------------------------------------------------------------
> Antonios Monokrousos
> Department of Mechanics                 email:    antonios at mech.kth.se
> Royal Institute of Technology (KTH)     phone:    +46 8 790 68 76
> Osquars Backe 18                        telefax:  +46 8 796 98 50
> SE-100 44 Stockholm, SWEDEN
>
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